Ibm Rs/6000 And Powerpc Options - Red Hat ENTERPRISE LINUX 3 - USING GCC Using Instructions

Chapter 4. GCC Command Options
-mcmodel=medmid
Generate code for the Medium/Middle code model: the program must be linked in the low 44
bits of the address space, the text segment must be less than 2G bytes, and data segment must be
within 2G of the text segment. Pointers are 64 bits.
-mcmodel=medany
Generate code for the Medium/Anywhere code model: the program may be linked anywhere in
the address space, the text segment must be less than 2G bytes, and data segment must be within
2G of the text segment. Pointers are 64 bits.
-mcmodel=embmedany
Generate code for the Medium/Anywhere code model for embedded systems: assume a 32-bit
text and a 32-bit data segment, both starting anywhere (determined at link time). Register %g4
points to the base of the data segment. Pointers are still 64 bits. Programs are statically linked,
PIC is not supported.
,
-mstack-bias -mno-stack-bias
With
-mstack-bias
by -2047 which must be added back when making stack frame references. Otherwise, assume no
such offset is present.

4.17.2. IBM RS/6000 and PowerPC Options

These options are defined for the IBM RS/6000 and PowerPC:
-m
-mpower
-mno-power
-mpower2
-mno-power2
-mpowerpc
-mno-powerpc
-mpowerpc-gpopt
-mno-powerpc-gpopt
-mpowerpc-gfxopt
-mno-powerpc-gfxopt
-mpowerpc64
-mno-powerpc64
GCC supports two related instruction set architectures for the RS/6000 and PowerPC. The
POWER instruction set are those instructions supported by the
RS/6000 systems and the PowerPC instruction set is the architecture of the Motorola MPC5xx,
MPC6xx, MPC8xx microprocessors, and the IBM 4xx microprocessors.
Neither architecture is a subset of the other. However there is a large common subset of in-
structions supported by both. An MQ register is included in processors supporting the POWER
architecture.
You use these options to specify which instructions are available on the processor you are
using. The default value of these options is determined when configuring GCC. Specifying
the
-mcpu=
cpu_type
-mcpu=
cpu_type
The option allows GCC to generate instructions that are found only in the POWER
-mpower
architecture and to use the MQ register. Specifying
, GCC assumes that the stack pointer, and frame pointer if present, are offset
overrides the specification of these options. We recommend you use the
option rather than the options listed above.
chip set used in the original
rios
implies
-mpower2 -power
87
and also allows